Owner of a 2017 GMC 1500 SLT. I too have the same noise as I had shook my bed side ways the noise came from the passenger rear wheel - I checked the shackle bolt nuts and found 2 that I retightened given each at least a full turn and a half but that didn’t help bed bolts sounds like they need to be checked- factory shocks look great with 30,000 miles on them - pretty bad even the GMC DEALERSHIP don’t know or don’t want to own up to the problem ~ sure is a good way to disown life time GMC customers
